1 8 INANITION ANT) MALNUTRITION 



nimmt immer merhr zu, unci zwar werdern jetzt umgekehrt wie zu Anfang die 

 zentralen Vakuolen immer grosser . . . Schliesslich zerfallt das Plasma (nach 

 etwa 3 Wochen) in eigenthiimlicher Weise, indem es sich zunachst in wenige 

 grosse Kugeln zerteilt, die wieder in kleinere sich auflosen, welche dann ganz 

 verschwinden. Der Kernhaufen bleibt schliesslich allein in der zusammenge- 

 falteten Gallerthiille iibrig, und leistet noch lange Widerstand." 



In Actinosphacriutn (a Heliozoan), and also in certain Infusoria, Hertwig 

 ('03a, '04) obtained by prolonged inanition a marked change in the nucleus- 

 plasma ratio, the nucleus becoming relatively enlarged. The significance of 

 this change will be mentioned later. Pearl ('06) found that poorly-nourished 

 individuals of the flagellate Chilomonas are reduced in size and slenderer in form. 

 Borowsky ('10) observed that Actinosphaerium eichhorni resists inanition 

 14-18 days. The nuclei become fewer (apparently by fusion), and in advanced 

 stages the cytoplasm undergoes marked vacuolation. 



Penard ('05) noted that Amoeba terricola may endure starvation for ten to 

 twenty days; but that other Amebae and Rhizopoda, free from "zoochlorelles," 

 perish in four or five days. Stole ('06) observed that in Amoeba proteus by 

 withdrawal of food for four days (as well as by overfeeding and other environ- 

 mental changes) binuclear cells are obtained, which return to the usual mononu- 

 clear form upon restoring normal conditions. Gruber ('n) found that Amoeba 

 proteus after six or seven days of starvation becomes sluggish, the plasma becom- 

 ing denser and darker. The cell becomes decreased in size, although the nucleus 

 gradually increases. After two or three weeks, the animal becomes rounded up, 

 degenerates and dies. During starvation in Amoeba diploidea, Erdmann ('10) 

 noted vacuolation and pigmentary degeneration. 



As an example of the effects of partial (calcium) inanition, Maas ('12) noted 

 a reduction of the calcareous skeleton in the Foraminifera Bilocularia and 

 Qiiinquelocularia in Ca-free sea water. Thompson ('17) stated (p. 415) that 

 " when Foraminifera are kept for generations in water from which they gradually 

 exhaust the lime, their shells grow hyaline and transparent, and seem to consist 

 only of chitinous material." 



Pratje ('21) has recently made an extensive and careful study of the changes 

 found in Noctiluca miliaris kept without food and observed alive. The normal 

 fat-droplets disappear gradually (in eight to fourteen days), so that the cyto- 

 plasm becomes transparent. The central cytoplasmic mass is greatly reduced 

 in amount, with fewer and thinner radial extensions to the periphery. There is a 

 corresponding increase in the peripheral vacuolar fluid, however, so there is no 

 appreciable decrease in the size of the whole cell. The nucleus becomes more 

 distinctly visible and more transparent. The nucleoli often become visible. 

 Thus far only the more fluid endoplasm has been affected, but as inanition pro- 

 gresses, the firmer, peripheral protoplasmic structures (cell membrane and 

 organs) are attacked and consumed. In about three weeks, all available sources 

 of energy are exhausted. Recovery by refeeding is now impossible, and death 

 soon occurs. " Fassen wir unsere Ergebnisse der Hunger versuche bei Noctiluca 

 zusammen, so finden wir, das im Hungerzustande zuerst die vorhandenen 

 Nahrungsstoffe und Reservesubstanzen aufgebraucht werden und erst dann 



